Browsing by Author "Kumar, P.C.R."

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Nonlinear optical studies of a novel pyrazoline
(2012) Janardhana, K.; Ravindrachary, V.; Kumar, P.C.R.; Umesh, G.; Manjunatha, K.B.; Ismayil
A novel pyrazoline, 3-(phenyl)-5-(4-hydroxyphenyl)-1-(2, 4-dinitrophenyl)-2-pyrazoline (PHDP) was synthesized using standard method and its chemical structure was confirmed using FTIR studies. The linear and non linear optical properties of the compound were studied using UV-Vis and Z-scan techniques. UV-Vis spectrum shows that the compound is transparent in the visible region and absorption in the UV region. The z-scan study shows that the compound possesses third and higher order optical nonlinearity. The calculated optical absorption cross sections indicate that the operating nonlinear mechanism is reverse saturable absorption type. The real part of the third-order nonlinear optical susceptibility ?3 was estimated and the closed aperture data shows that PHDP possess negative nonlinearity. � 2012 American Institute of Physics.
Third order optical non-linearity of a novel chalcone derivative through Z scan technique
(2013) Janardhana, K.; Ravindrachary, V.; Kumar, P.C.R.; Umesh, G.; Manjunatha, K.B.; Ismayil, N.
A novel chalcone derivative 4-{ (1E,3Z)-3-(4-bromo phenyl]-3-[2-(2,4- dinitrophenyl) hydrazinylidene] prop-1-en-1-yl phenol [BPDP] has been synthesized and structurally characterized by NMR and FTIR studies. The third order non-linear optical properties of the BPDP have been studied using single beam Z scan technique with a nanosecond-pulsed Nd: YAG laser source at 532 nm. The coefficient of non linear refraction (y) of the compound is found to be negative as revealed by the signature of closed aperture data. The results obtained under open aperture configuration indicate that the material exhibits reverse saturation absorption. The magnitude of real part of third-order optical susceptibility 3)) and of molecular second order hyperpolarizability (Yh) are found to be -3.5x1w2U) m2W2 and -5.9x1W' m5W2, respectively. The thermo gravimetric analysis shows that the material possesses a very good thermal stability up to 203°C.
Third order optical nonlinearity of a pyrazoline derivative
(2011) Janardhana, K.; Ravindrachary, V.; Kumar, P.C.R.; Yogisha; Poojary, B.; Manjunatha, K.B.; Ismayil
A new pyrazoline derivative 3-phenyl-5-(4-N,N-dimethylaminophenyl)-1H-2- pyrazoline (PDHP) was synthesized using standard method. The structure of the compound was established based on 1H NMR spectrum. The third-order optical nonlinear properties of PDHP compound were measured using nanosecond Z-scan method The measured nonlinear absorption coefficient ? is 0.27�10-10m W-1. The magnitude of third order susceptibility is Re?(3)==19.94�10-13 esu and Im?x (3)=5.85�10-13 esu. These experimental results reveal that the PDHP may be a good candidate for optical limiting applications due to its reverse saturated absorption phenomenon. � 2011 American Institute of Physics.